As an existing coaxial connector plug, a coaxial connector plug disclosed in Japanese Unexamined Patent Application Publication NO. 2013-98122 is known, for example. FIG. 12 is a cross-sectional structure view of a coaxial connector plug 510 disclosed in Japanese Unexamined Patent Application Publication NO. 2013-98122. FIG. 13 is a planar view of a center conductor 514a, viewed from the front side, of the coaxial connector plug 510 disclosed in Japanese Unexamined Patent Application Publication NO. 2013-98122.
The coaxial connector plug 510 includes, as shown in FIG. 12, an outer conductor member 512, a center conductor 514a, and insulation member 516. The outer conductor member 512 includes an outer conductor 512a and an outer terminal 512b. 
The outer conductor 512a is formed in a cylinder shape extending in the vertical direction. The outer terminal 512b is extended to the lower side of the outer conductor 512a, and is bent into a direction which is distanced from the outer conductor 512a when viewed from above.
The insulation member 516 is a plate member configured to close an opening at a lower end of the outer conductor 512a and is made from resin. The center conductor 514a is integrally attached to the insulation member 516 through insert molding, and is provided in a region surrounded by the outer conductor 512a. 
Note that, as shown in FIG. 13, a hole H is provided on a side surface of the center conductor 514a. Further, as shown in FIG. 12, the insulation member 516 penetrates into the inside of the center conductor 514a through the hole H. This suppresses the center conductor 514a from being easily detached from the insulation member 516 in the coaxial connector plug 510.
It is required to lower the height of the above-described coaxial connector plug 510 in the vertical direction (hereinafter, to lower the height is referred to as “low-profiling”).